What are the three basic parts of a modern firearm?

The three basic parts of a modern firearm are indeed the action, stock, and barrel.

The action is the mechanism that loads, fires, and ejects cartridges, making it crucial for the functioning of the firearm. The stock serves as the part of the firearm that provides stability and support when aiming and firing, allowing the shooter to handle the firearm more effectively. The barrel is where the bullet travels through when fired, and its length and design significantly influence accuracy and velocity.

Together, these three components form the essential framework of a firearm and are necessary for its operation. Understanding these parts is fundamental for safe firearm handling and maintenance, as each plays a distinct role in the overall functionality of the weapon.